See what happened after a year long ordeal modifying this speaker.

By: Gary DeRoy (GTX_SlotCar)                        

INTRODUCTION BACKGROUND BIC DV62 CLR-S - IMPRESSIONS THE EXPERIMENTS

LAST ROUND TESTING WORKING MODIFICATION FINAL TWEAKS CONCLUSIONS

INTRODUCTION

    Auditioning new speakers can be tricky. There are times when a pair sounds so bad that you can quickly eliminate them, but the choice among good sounding ones isn't something that can be done in a minute or two. Often, each new speaker you listen to sounds better than the one before until you spend a lot of time with it. It's even worse when you are building or modifying them yourself because you have to contend with something known as psycho-acoustics. That's when any modification you make sounds better to you. This is so real that it can only be overcome with an honest, blind audition. You can do it yourself with a helper, but you're better off finding someone else, who's opinion you trust, to do it for you. There's also a lot of misinformation in reviews and online. Instead of falling for these, you should spend time doing some real research yourself.

    It seems appropriate to tell you a little about me. After high school, I went to school for electronics in 1968 where I had a 4.0 gpa and was president of the student council. After school, I spent a couple years in the Army and then managed a Hi-Fi store for a large, national company. During the next 5 or 6 years, I became friends with some of my employees and also those of several competing businesses. Many of them are still friends today. When I left to go to college for marketing, I worked for the university's A/V department as a TV camera man and also repairing audio/video equipment. I'm telling you this so you'll know that, although I'm not a speaker design engineer, at least I have a basic knowledge of electronics and have had the opportunity to listen to hundreds of speakers (and everything else to do with Hi-Fi audio). If you've glanced over other articles on my web site, you've noticed that I have a prodigious desire to tweak and modify things to try to make them better. My musical taste is eclectic. I've always enjoyed old fashioned rock 'n roll, and I'm growing particularly fond of acoustic music and some female vocalists (jazz, easy rock, big band).

    The article that follows is a year long trial of what I went through to get a great sounding set of affordable surround speakers for my home theater system.


BACKGROUND

    Around 1979 or 80, I visited a good friend that was working at a high end Hi-Fi store (and still does today). I bought from him a set of 3D Acoustics 3D6 satellite speakers and 10B subwoofer for

about $500. These speakers were one of the first sets available as satellites with a separate subwoofer. Stereo Review compared them to their favorite set of speakers (that cost over $5000) by saying that the only way they could tell which speakers were playing was to look at the position of the switch (unless the speakers were driven to  extremely high levels, in which case the expensive speakers did sound slightly better). It wasn't just the quality of the sound they  produced, but their almost unparalleled imaging, left/right, front/back, up/down, that made them great. I still have these speakers today. I've upgraded the crossover components (same values, just better electronics and wiring) and replaced some of the drivers (original drivers are still available). 3D Acoustics was one of those companies that had a great product and poor marketing. The company only lasted a few years. The 3D6's imaged so well that I could put a dummy center channel speaker on my TV, put the surround in 'phantom center' mode (left and right speakers produce the center channel) and people would swear the center channel was working. In fact, they had to get within 6 inches of the center speaker before they realized there was no sound coming from it. That's great imaging.

    Of course, I still wanted a center channel speaker, so my quest began. I use my home theater for both music and movies, so finding a new speaker was going to be hard, and finding one to match the timbre of the 3D6's would make it even harder.

BIC DV62 CLR-S - FIRST IMPRESSIONS

    I was fortunate that friends in local stores could loan me some to try. I also bought and returned some from other local dealers (agreements made before purchasing) and even bought a couple online. There were a few that sounded great, but they weren't a perfect match with the 3D6's and they were $700 or more. That price was out of the question. Finally, I came across a BIC DV62 CLR-S at a reasonable price online. I paid about $80 for it including shipping. This speaker really surprised me even though I'd read about it on audioreview.com and had seen it's highly favorable ratings. I played it for a few hours to break it in before doing some real testing and comparing it with the 3D6's. The sound was so clear, airy and detailed that I couldn't help but like it, but it still wasn't a great timbre match for the 3D6's. I did more reading and found that a guy named Ed Frias was offering a modified crossover at a reasonable price that was supposed to make these speakers sound even better. I contacted Ed to get more information and found him to be personable and knowledgeable.

    At this point I decided it was time for someone else to compare some of the speakers I had acquired. I invited my good friend over to audition them. I had 3 speakers for him to listen to; the 3D6's which he already knew a great deal about, the BIC and another popular speaker that I won't disclose.

We found a good musical passage that he was familiar with in the Eagles DVD "hell freezes over", the intro to 'Hotel California'. It's great acoustic guitar and the type of music I listen to most. Volume controls were set to strongly emphasize the right speaker, which is the one we tested. Before he came over, I used a db meter to set volume levels for each speaker. First up was the 'other popular' speaker. After about 15 seconds he said "Next". I agreed, although it was a good center channel speaker for movies and reasonably priced, it didn't handle this music very well. Next up was the 3D6. As expected, it performed almost flawlessly with clear, clean and snappy notes with all the overtones. We listened to it several times and made comments about what a great deal these speakers were, and are in today's market. They would be hard to beat. Finally it was time for the BIC. I had covered the logos with tape so he couldn't tell what it was. He asked me how much I paid for it, but all I told him was that I probably paid too much. I didn't want him to dismiss it because of the price. After the first few seconds, he was almost floored. He said that not only was the sound detailed, dynamic and clean like the 3D6, but it also had a certain airy quality or transparency to it that's hard to explain. It was almost like the speaker wasn't there at all. We listened to it several more times, then swapped back and forth between the 3D6 and the BIC a few times. Hands down, the BIC was the winner. I then hooked it up as the center channel and we listened to other music such as female vocals from Linda Ronstadt's "Sentimental Reasons" and Norah Jones' "Come away with me", and more acoustic guitar from Nina Gerber's "not before noon" and selections from John Fahey and Laurence Juber. When I finally pulled the tape off the logos, he couldn't believe it. He wanted to bring the BIC to the store and do the same type of blind test with the salespeople there.

    I found another good deal on 2 more BIC DV62 CLR-S's and ordered them thinking that I'd use 3 of them as my front speakers. I was curious about Ed Frias's modification, partly to see if it really could make the BIC's sound even better, and partly to see if it would provide a better timbre match for the 3D6's. Also, at very loud levels, I thought some female vocals, mostly Linda Ronstadt's, were a little bright, although my friend did not agree.

    I probably had 40 hours on the original BIC when the other two arrived. I connected one of them and soon noticed that it didn't sound quite as good as the old one. Thinking it might be a bad speaker, I tried the other new one and that yielded the same results. Even a good sounding speaker can sound much better when it's been played for a few hours. I removed the crossover network from my original BIC and sent it off to Ed Frias. In the mean time, I connected the 2 new ones to the left and right channels, used a 3D6 as the center, and played them several hours each night.

    Ed had the modified crossover back to me within a few days. I installed it and played the speaker immediately. My first impression was that the modified speaker did sound better. The tonal quality was similar but the brightness of Linda's voice at high volume levels was gone. The timbre was still not a good match for the 3D6's, but at this point it didn't matter to me anymore. I listened to a variety of music and movies for the next couple evenings with the modified BIC as center and the others as left and right. I was trying to decide if I should send the other crossovers to Ed or just duplicate the components myself. As much as I liked the modified BIC, by the time the weekend came around I felt like something was missing. It was time to start comparing again. The first thing I did was to put the emphasis on the right speaker and listen to the same Eagles' passage that I played when my friend auditioned the speakers. Once again, the sound was great. Maybe there was no problem and it was just my imagination. Then I swapped the right speaker for the Frias modified center speaker. Within seconds of listening to the modified BIC, the problem was apparent. The most charming aspect of this speaker, it's airy, transparent sound, was missing. Well, not completely, but enough so that I noticed the difference right away. It was like it's soul had been taken.

    Needless to say, I was disappointed. What I thought would be a cheap and easy solution would have to be abandoned. Don't get me wrong; the Frias modified speaker did sound good, but the compromise was too great for me. If I didn't use them so much for music, I might have remained happy. Now I had to figure out something else. I thought that I could do some modifications to the original crossover (change some values, add a zobel or choke, etc.) and maybe come up with something that pleased me. And so, the longest part of the journey began.

 
THE EXPERIMENTS

    I knew a fair amount about crossover design, but scoured the internet for more information. Eventually I figured out 2 crossover scenarios that I thought would be viable and ordered some high quality resistors and capacitors from Parts Express. My speaker stands are screwed through the carpet down into the sub-floor (don't worry, when the screws are removed the carpet bounces back and you can't even tell they were there). I measured off 39", put masking tape on the carpet to mark the spot and placed a db meter on a tripod to take measurements. Then I used a tone generator through my PS Audio power amp (noted for it's flat frequency response) and started taking frequency measurements. I used 80db at 1000 Hz to set the volume and mapped a chart in 100 Hz increments for the original speaker, the Frias modified speaker and each speaker I modified. I had to stand well to the side of the db meter so I wouldn't interfere with the measurements. My intention was to include the charts in this article, but there are so many and this article is so long that I've decided against it. 

    The timbre on the Frias and standard BIC is very close. They could work pretty well together in a surround sound setup, but it did surprise me that their frequency curves were so similar. My original goal was to make a crossover that would produce a flat frequency response from 200 Hz to at least

10,000 (I use a Shiva sub-woofer and my receiver controls the crossover). I did, in fact, accomplish this to a great degree, but the results were not spectacular. What I mean is, the speaker sounded good, but certainly not great. I moved the setup outdoors to check the results, but except for the very low and very high ends, the response measured about the same. I was curious about this and tested the response of the 3D Acoustics 3D6 and another high end (about $700) speaker which sounded very good. Much to my surprise, neither of them produced a flat response. By that I mean a response that was within 3db from 200 to 10,000 Hz. I summarized that even though some great sounding speakers may have a flat frequency response, it isn't necessary to have a frequency response that flat in order to have a great sounding speaker. (In fact, I later found out that many highly acclaimed, expensive speakers do not have particularly flat frequency responses.)

    It's important to note that the total value of a crossover network depends on some values of the voice coil in each driver. As the voice coils heat up (from playing for long periods or at higher volume levels) their values change and so, of course, do the crossover frequencies. Even playing highly distorted heavy metal music will increase the temperature of the voice coils compared to acoustic music at the same listening level. This explains a lot. Let's assume a crossover is designed with a certain roll off in mind and the crossover frequency at 2800 Hz with the voice coils at 93° (in reality, tweeter and midrange speakers won't have the same temperature at the voice coils). Now we'll assume even further that one person is listening to acoustic music in a large room and driving the speakers at 95 db at 1 meter, and another person is listening to the same music in a smaller room and driving the speakers at 70 db at 1 meter. The temperature difference in the voice coils would

change the crossover frequency. A casual listener might not notice the difference in the way the speakers sound, but a true audiophile certainly would. Depending on the music, the voice coil in the midrange driver may not heat up much compared to the voice coil in the tweeter, or less likely, the reverse could be true. Theoretically, a speaker could sound great at one volume, not so good at a louder level, and pretty good again at an even louder level, depending on the type of music at each volume. This could explain why Linda Ronstadt's voice seemed a little bright, but only at very high volume levels. It also explains why two people can describe the same speaker differently. And finally, it explains why Stereo Review said the $5000 speakers sounded better than the 3D6's at extremely loud volumes. Hopefully, very expensive speakers have expensive drivers with voice coils that handle heat better and so, they'll sound better than a great pair of cheap speakers under certain listening conditions. (Naturally, the environment the speaker is in will make a big difference. Most of us don't have acoustically dead listening rooms. Mine is a little bright as it slightly emphasizes the higher frequencies).

    Over the next few weeks I tried several combinations of crossover modifications, most of which had little to do with my original design. It wasn't total guess work, but more like educated guess work. Sometimes I modified the crossover at the tweeter, the midrange drivers or both. I ran wires out through the ports with switches on them so I could switch components or take them in and out of the circuit for easier comparisons. My wife was getting irritated by the constant tape marker on the carpet as I was still measuring the frequency response of each modification. After what seems like a hundred combinations, I did find 3 that were promising. Each sounded quite similar to the Ed Frias modification, but with less destruction of the transparency. At this point I stopped taking measurements and finally pulled the tape off the floor. I listened to these 3 versions for another couple weeks and finally settled on one. I liked it so much that I modified the other speakers this way and listened to them for the next 3 months in complete bliss.

LAST ROUND TESTING

    Eventually, I realized that I had never actually done a blind test of this modification. Certainly I couldn't fall prey to psycho-acoustics, and I had auditioned the new modification extensively, comparing it to both the standard BIC and the one with the Frias modification. Still, I wanted to prove that I wasn't kidding myself and a blind test was, after all, the scientific thing to do. I put one speaker back to the standard crossover and reinstalled Ed Frias' in another. As a helper, my teenaged daughter proved to be more patient than my wife, and keeping with the spirit of the test, she was also quite tricky. By this time, one speaker had the BIC logo in it's standard place, but I had moved it on the other 2 so they could stand on end. On one of these I made sure that, with the logo at the bottom, the black terminal was on top, and on the other it was on the bottom. This way I could identify each speaker. A common ground was run to each speaker as they sat side by side (2 at a time), and my daughter only had to move the red wire to

switch them. All the speakers produced the same db level at 1000 Hz and with white noise so it wasn't necessary to adjust the volume. The first round of tests was between my mod and the Frias mod. I closed my eyes (and didn't peek) and held the remote in my hand with my finger on the song track button so I could reset it easily. No matter how she tried to throw me off track, I picked my mod as the best sounding each time. When it came for the standard BIC and my mod, things were more difficult. On 2 or 3 passages I admitted that I couldn't make a choice because they sounded the same. On others, like the intro to 'Hotel California', the choice was easier. In the end, although all 3 speakers sounded good, there was a clear winner, a 2nd and 3rd place. The standard BIC came in first, my mod 2nd and the Frias mod 3rd. Yes, I was surprised at the results and almost devastated. I don't know what happened. Maybe it was because the speakers had over 100 hours on them by now. I'm not sure. The fact is that in each test between the speakers with the Frias mod and my mod, I picked mine each time, and in the tests between my mod and the standard BIC, I picked the standard one each time I was able to make a choice. My daughter didn't know which speaker was which, only that I was picking the same one each time. So in that respect, it wasn't even close. The winning speaker wasn't chosen a majority of the time; it was chosen every time. All that work, all those modifications and all that time - and I ended up right where I started.

    I left the speakers as they were, called a friend (not the same one who originally auditioned them with me) and in a couple days brought them to the store where he worked. At different times there were either 4 or 5 employees auditioning them. I covered the logos again and started out with the standard BIC. They had an elaborate setup and the BIC was set as a center channel. Sometimes it ran alone in mono mode and other times it was accompanied by a pair of other speakers. The BIC performed great no matter what they threw at it and they wanted to know if they could carry the brand and what price range it was in. Although it beat most of the speakers they compared it to, we did listen to two speakers, in particular, that did sound better than the BIC, but they were $800 and $1200. They may have had others for less money that sounded better, but we didn't compare it to everything they had. To tell the truth, I wasn't so interested in this part of the test as what was to come next. I still hadn't told them the brand, but asked them to listen to 2 other variations of the speaker. About a half hour and several musical passages later, they all came to the same conclusions. The standard BIC came in 1st, my mod 2nd and the Frias mod 3rd. In fact, the only one they would be interested in carrying was the standard speaker and they were very enthusiastic about it.

    I finally revealed the BIC logos and told them what I paid for the speakers. I was unprepared for what happened next and I can only describe it as a lesson in human behavior. Suffice it to say that before they knew the brand and price, they had nothing but praise for the BIC.


WORKING MODIFICATION

    It was time to review the events of the past few months, put the facts in order and make some decisions. 

(1) The standard BIC speaker sounds great. It's airy, dynamic and transparent. 

(2) It doesn't image as well as the 3D6's, but except for a pair of Magnepans and a couple other $2000 plus speakers, I haven't heard anything else that does. 

(3) The fact is, the BIC's do image OK, but speaker

placement and angle are critical (as they are with most speakers). Imaging is not a problem if you're sitting in the "sweet spot".  In stereo mode, I can still place Linda Ronstadt's voice ("Am I Blue" and "Sentimental Reasons") in the center of the stage and the trumpet / sax behind her and a little to the right. It's a little more vague than the 3D6's, but it's there. I've heard expensive speakers that didn't image well at all. When listening to DVDs like Paul Simon's "You're the One" in 5.1 or DTS, the imaging is great. 

(4) None of the modified crossovers affected the imaging at all. 

(5) On a couple songs, with female vocals at loud volumes, I thought the BIC's were a little bright; but not everyone agreed. Of course, my listening room also sounds a little bright. 

(6) In the end, none of the modified crossovers could improve on the sound.

    With my thoughts organized, I realized the slight brightness was the only thing I wanted to, or could, change, and the easiest way to do this was with an L-Pad on the tweeter (actually, it was recommended by the chief engineer of a speaker manufacturer). I could have spent time and money trying different values, but I decided to take the easy way out and bought three 8 ohm variable L-Pads from Parts Express for under $8 each. They came with instructions, installation was easy and they did the trick perfectly. I could leave them off most of the time, and when I needed them I found that about 1/8 of a turn worked well for getting rid of the brightness and still left the transparency intact. This is exactly what I wanted all along.

FINAL TWEAKS

    Now that I had my BIC speakers sounding the way I wanted them to with any musical selection, there were a couple other things I wanted to try. I noticed that the speakers sounded better on the stand than on top of the TV. Since the stand was screwed to the floor, this was

expected, but the one on the TV would sometimes give a slight resonance or buzzing sound. This didn't happen often and it was subtle, but it did happen sometimes at loud volumes. My first thought was that it was reflections inside the cabinet, so I bought some fiberglass acoustic insulation from Radio Shack. It was 1 inch thick, so I peeled it in half making it 1/2 inch thick because I didn't want to change the values inside the cabinet too much. I pulled out the standard acoustic fill and lined the back, bottom and one side with the new material. That would eliminate any internal reflections. It didn't sound worse, but it also didn't help. The BIC's are made from half inch MDF, which should be plenty for eliminating cabinet resonance in a speaker this size. You can feel slight vibrations on the outside of the cabinet, but not much. I should have realized right away that the objectionable sound was coming from my TV cabinet, not the speaker. My HDTV, like any other, is basically a large, hollow, thin plastic box with a screen that acts like a passive radiator. It's the worst possible place to mount a speaker. To isolate the center channel from the TV cabinet, I first used small rubber feet at the front of the cabinet and rubber door wedges (door stops) at the back so the speaker would tilt down. This worked well, but I eventually just folded small strips of the fiberglass insulation and used them for the speaker legs. The ones in the back are thicker than the ones in front, so the speaker still tilts down. They hardly show and do a pretty good job. You can buy Isolators (often used for turntables), but I'm not sure of the cost. I would

prefer to mount the speaker to something solid instead of trying to "float" it, but this is easy and it works.

    The other thing I wanted was to control high frequency diffraction. At first I used some "loose" foam strips (like those used to wrap computer components such as motherboards, video and sound cards, etc., and also used on foam paint brushes) and just fastened them (with double sided tape) between the narrow sides of the cabinets and the tweeters. Eventually, I removed them and opted for some stick-on felt instead. I'm not sure if it does as much for diffraction, but it should stop high frequency reflections bouncing back from the grill cloth. Either way works, but the felt, which happened to be red, looked cool. The theory is sound, but whether you'll actually hear a worthwhile difference is up to you. It doesn't hurt.

CONCLUSIONS

    I purposely didn't mention the brands of the speakers used for comparison. If I said the speakers didn't sound very good and the reader owned and liked them, it would only make him angry. Giving the brands of the ones that sounded as good as or better than the BIC's would have made it possible for anyone in my area to determine which store did the auditioning. Since they didn't carry the BIC's, which out performed all but their most expensive models, they didn't want to be identified. I'm just keeping a promise made to friends. And after all, this article is about the BIC DV62 CLR-S, not the other brands. In fact, I'd also like you to keep in mind that this article may not be applicable to the BIC bookshelf or tower speakers.

 

    In reading other reviews, I've noticed people mentioning the use of acoustic fill to eliminate cabinet resonance (boom). I know that some acoustic fill makers would like you to load your speakers with their product, but it's not the right way to fix this problem. Acoustic fill, used properly, is good for eliminating sound reflections inside the cabinet. To stop the resonance, make the cabinet out of thicker MDF (or wood), or install internal bracing. MDF (or wood) glued between the walls of the cabinet would work fine. Glue them at the walls and where they cross each other. Speakers are engineered to work with a certain cabinet volume. On ported speakers (like the DV62 CLR-S), the ports are tuned to the cabinet size and driver characteristics. Adding acoustic fill has the effect of increasing the cabinet volume (size). While this is more critical on a sealed system, it

affects the engineering of all speakers. Psycho-acoustics may make your poly-stuffed speakers sound better to you, but in reality they'll probably sound worse. If you don't know how to tune the enclosures to the resonant frequency of the drivers (or don't even know what I'm talking about), don't stuff the BIC's with acoustic poly-fill. If you think you hear a booming or hollow sound and the speaker is sitting on top of your TV, that could be the problem.

    I've also read that a couple people were thinking about adding 2 center channel speakers, side by side. Years ago, we used to run stacked Advent speakers and they really did sound good this way. However, a center channel speaker is used to pinpoint sound on the stage in front of you. Running 2 of them side by side might ruin the imaging, making it vague and muddy. 

    I never thought I'd find affordable speakers that would replace the 3D Acoustics, which, by the way, are now connected to a recently purchased, mint condition Marantz 2225 receiver (they image so well that I couldn't part with them), but the BIC DV62 CLR-S is a tremendous value. With it's dynamic, transparent and detailed sound, it out performs many speakers costing 8 to 10 times as much. Break them in for about at least sixty hours before making any final conclusions or changes. If they sound too bright, try installing an $8 L-Pad. Ed Frias' modification also sounds good and may be just the thing for you. I didn't like the slight loss of transparency, but you may not mind it. All the auditioners that listened to my BIC's picked the stock speaker as sounding the best in a blind listening test, but it doesn't mean that you'll agree.

   For what it's worth, and after all I've been through, I haven't even used the L-Pads to control the sound in over 2 months and they don't seem to sound bright anymore. My hearing hasn't changed. I still hear up to almost 17,000 Hz in my right ear and just over 14,000 in my left. At least I know the L-Pads are there if I need them.

   Every time I turn on my home theater system, I'm impressed with the sound of these speakers. I couldn't be happier with the choice I made and I know I wouldn't have been satisfied if I hadn't tried the modifications. So, it wasn't a complete waste of time.

   If you'd like more information about BIC America speakers, you can visit them on the web at www.bicamerica.com.

Gary DeRoy

March 24, 2003