DIY Waveguide loudspeaker kit

[gedlee]

Perhaps what you are really doing is:

1. running your main speakers full range (and letting their natural rolloff below 50hz protect them from overdrive)
2. using your receiver to SUM content from your main speaker channels below 150hz to the LFE channel, creating what is called a subwoofer channel (which is distinct from an LFE channel).
3. using this subwoofer channel as the input for each of your subwoofers, which you then adjust for frequency and level.

If this is the case, then it would all seem to make some sense.

Yes. Parametric EQ can also help as well. Do you have parametric EQ in your subwoofers? If not, how do you deal with room modes?

Your discussion is all semantics to me. The output on the receiver is labeled "LFE", but yes in "stereo" it is a mono sub channel, but in DVD it is the LFE "PLUS" which means that LF energy from all channels is also sent to the LFE channel - an ideal situation for what I do. Different receivers do this differently but in mine I can set the LP frequency above 120 Hz in "PLUS" mode.

When you use multiple subs in a room with substantial LF damping there really aren't problem modes that need EQ. Only in a few cases have I found the need for EQ at these frequencies.

 

[gedlee]

Could someone explain to me the advantage of using a boutique subwoofer instead of a Costco subwoofer?

You might argue that the Costco sub will have lousy power handling. If that's the case, buy four of them. That increases your SPL limit by 12db.

You might argue the Costco sub isn't as handsome as an audiophile sub. That may be true, so hide it! No one wants to look at three subs anyways.

You might argue that the Costco sub has lousy frequency response. While some cheap subs are designed with a hump in the midbass, there are plenty of inexpensive powered subs that measure well and have predictable crossovers and EQ built in.

Last but not least is price. Spending $750 on three Costco subs and pairing them with a $1200 kit seams reasonable. Spending $3000 on three boutique subs seems unnecessary with $1200 mains.

I've always been mystified by the use of exotic subwoofers in the home. In car audio, they make a lot of sense, because box size is king in mobile audio. Also, car subs function in "pressure mode" due to the small dimensions of the cabin. Exotic subs also make sense in pro audio, where dozens of subs are in play and each is being fed thousands of watts.

In the home, not so much.

The Costco comment was perhaps somewhat facicious, but John, you get the point and I agree with you. The fact is that I don't use Costco subs, I use bigger units with higher power, BUT I don't use boutique subs just like you say.

 

[gedlee]

HT is the ONLY place a subwoofer matters. You don't need one for music, providing you have real main speakers.

Good quality subs beat one note boom boxes and over eq'ed, over driven poop producers any day.

I don't agree with this and obviuosly neither do the reviewers of my rooms.

 

[MJL21193]

I don't agree with this and obviuosly neither do the reviewers of my rooms.

Which part? The need for a sub for music or the adequacy of the cheap HT in a box subs?

I have always had reasonably good speakers. I've had good subs and I've heard cheap ones. Music, IMO is best through 2 good speakers, ones that cover the frequency range. As it was intended to be. I turn off my sub for music. Likewise, I don't listen to music is surround.
As for HT, I'd rather no sub than a deficient one.

 

[publius]

Your discussion is all semantics to me. The output on the receiver is labeled "LFE", but yes in "stereo" it is a mono sub channel, but in DVD it is the LFE "PLUS" which means that LF energy from all channels is also sent to the LFE channel - an ideal situation for what I do. Different receivers do this differently but in mine I can set the LP frequency above 120 Hz in "PLUS" mode.

When you use multiple subs in a room with substantial LF damping there really aren't problem modes that need EQ. Only in a few cases have I found the need for EQ at these frequencies.

Thank you Dr. G. Have you posted the frequency response of your room? I would be curious to see what response you have found to sound best. If not, could you describe it? E.g., do you shoot for dead flat response, rising response in the bass with a 5db peak around 50hz and rolled off below that, etc.

 

[gedlee]

Thank you Dr. G. Have you posted the frequency response of your room? I would be curious to see what response you have found to sound best. If not, could you describe it? E.g., do you shoot for dead flat response, rising response in the bass with a 5db peak around 50hz and rolled off below that, etc.

I go between perfectly flat and about a 2 dB rise at maybe 50 Hz. Some rooms sound different than others, but in general I would say flat is best unless you have a notable lack of bass. If I can dig up my room response I will post it.

I believe, as many others have noted, that true CD sounds bright if EQ'd perfectly flat to 16 kHz. I drop this by a few dB at the top with the curtains that I use in front of the speakers and this seems to yield the best results. If you don't use curtains and you don't use a treble control and you use a flat EQ in the crossover, I guarantee you that you will find this bright as we are just not used to hearing wide coverage at 10 kHz.

 

[gedlee]

Which part? The need for a sub for music or the adequacy of the cheap HT in a box subs?

I have always had reasonably good speakers. I've had good subs and I've heard cheap ones. Music, IMO is best through 2 good speakers, ones that cover the frequency range. As it was intended to be. I turn off my sub for music. Likewise, I don't listen to music is surround.
As for HT, I'd rather no sub than a deficient one.

No one is suggesting using totally incompetent subs. Even the Costco ones are Infinity and Klipsch, not junk.

But only two source locations for the low end will not yield a very good response and then these mains need to be huge to go low enough. The two speaker approach is just not optimum, even for stereo.

 

[MJL21193]

But only two source locations for the low end will not yield a very good response and then these mains need to be huge to go low enough. The two speaker approach is just not optimum, even for stereo.

Funny, but it works for me. Mains don't need to be huge. I have three way speakers with fairly good low end response, fairly good efficiency and capable of fairly high SPL. They sound great for music, and I do like it loud.
By themselves they don't cut it for HT though.

For HT, there is not enough bass production. Also, we need a centre channel and rear surrounds. But, this is HT, not music.

It just seems like your system is optimized for HT, not for music.

 

[gedlee]

It just seems like your system is optimized for HT, not for music.

Thats not what the reviews say. Read them!

REDWINGS RULE!!!!

 

[limono]

Can't we just focus for now on DIY speaker kit which will be 10" with 80-100Hz bottom and options and leave the Summa or 12" 15" out of it? When the first batch will be delivered and when the first (beta??) testers are going to write or report on the sound?
Is there a prototype to listen too? I do like an idea of a curtain at a front of a speaker (it solves speaker finish problem too
Regards, L

 

[Salas]

I go between perfectly flat and about a 2 dB rise at maybe 50 Hz. Some rooms sound different than others, but in general I would say flat is best unless you have a notable lack of bass. If I can dig up my room response I will post it.

I believe, as many others have noted, that true CD sounds bright if EQ'd perfectly flat to 16 kHz. I drop this by a few dB at the top with the curtains that I use in front of the speakers and this seems to yield the best results. If you don't use curtains and you don't use a treble control and you use a flat EQ in the crossover, I guarantee you that you will find this bright as we are just not used to hearing wide coverage at 10 kHz.

Maybe you use a -2 db slide from 2k to 10k? That sounds good in general.

 

[publius]

Earl,
Very interesting stuff. The DDS ENG 1-90 Pro waveguide is mentioned a lot for its good sound. Did you design it? Someone mentioned you did. What do you think of it? How low can it xover well? How does it compare with your waveguides? Thanks.

it loses directional control around 1.5k.

http://htguide.com/forum/showpost.php4?p=323223&postcount=274

From what people say, it performs okay, but is a little small for a nice cross to 15" or 12" woofer. Dr. G's will probably be better.

 

[publius]

Dr. G.:

The off-axis plot at the bottom of these pages (which are amazing btw) show the ESP15 has a dip around 1.4khz that gets worse further off-axis and is not present on the ESP10 plot. What is causing that? Is it that the ESP15 could benefit from a slightly larger waveguide or is it something else?

http://www.ai-audio.com/products_esp15.html

http://www.ai-audio.com/products_esp10.html

Also, the off-axis plots on the ESP15 are flat from 1.2khz up, while on the ESP10, they are flat from about 2khz up. What effect does this have on how these two speakers sound?

 

[AJinFLA]

Re: A visit with Earl Geddes - Review of Summa 15's

Will better electronics make a better listening experience? Perhaps.

Anand.

Better..?? Better how?

cheers,

AJ

 

[gedlee]

Dr. G.:

The off-axis plot at the bottom of these pages (which are amazing btw) show the ESP15 has a dip around 1.4khz that gets worse further off-axis and is not present on the ESP10 plot. What is causing that? Is it that the ESP15 could benefit from a slightly larger waveguide or is it something else?

http://www.ai-audio.com/products_esp15.html

http://www.ai-audio.com/products_esp10.html

Also, the off-axis plots on the ESP15 are flat from 1.2khz up, while on the ESP10, they are flat from about 2khz up. What effect does this have on how these two speakers sound?

I described this before. The ideal waveguide would be more like 18" across. This would elliminate the midrange narrowing that you are talking about.

I seldom if ever make subjective comments. But having listened to the SUMMAs for five years now and comparing them to other speakers and the reviews of other listeners, I'd put those speakers up against any speaker at any price. I have had, at most an hour or two listening to the ESP10 and ESP12. They are more similar to the 15 than different, but they are not quite as "smooth" as the 15. This is reflected in the measurements. Bigger is better in speakers. You want that "ultimate sound" it takes a big speaker and a bit of money.

 

[gedlee]

Can't we just focus for now on DIY speaker kit which will be 10" with 80-100Hz bottom and options and leave the Summa or 12" 15" out of it? When the first batch will be delivered and when the first (beta??) testers are going to write or report on the sound?
Is there a prototype to listen too? I do like an idea of a curtain at a front of a speaker (it solves speaker finish problem too
Regards, L

I don't see any reason not to discuss the bigger speaker options.

I am casting the first waveguides this week. The first deleiveries could be next week.

I will probably havea pair here to audition by next week. But they won't have the advantage of the room that the Summas are in. I'm not giving up my SUMMAs!!

Oh, and for a name I'm going to use Nathan10, Abbey12 and Lidia15. Summas will always be the composite cabinet models. There maybe an Abbey plus, 1 12" woofer and 15" waveguide.

 

[MEH]

Change of plans?

Am I reading you correctly, Earl, that in addition to Nathan10 kits, you have now changed your plans and will definitely offer Abbey12 and Lidia15 kits? Or are these still just possibilities awaiting the success of the Nathan10 kits before becoming reality? If the larger waveguide kits are a definite go, do you have any estimate for when they will be available and at what initial price?

 

[gedlee]

Re: Change of plans?

Am I reading you correctly, Earl, that in addition to Nathan10 kits, you have now changed your plans and will definitely offer Abbey12 and Lidia15 kits? Or are these still just possibilities awaiting the success of the Nathan10 kits before becoming reality? If the larger waveguide kits are a definite go, do you have any estimate for when they will be available and at what initial price?

I'd say based on response, the 12" is s deffinite go, I've already started on that one, but the Lidia15 is probably down for the count. No one has shown an interest in that size. There might be an Abbey_plus, a 12" woofer and 15" waveguide. There is a little interest in that, but not enough right now for me to commit to it.

 

[mike galusha]

Re: Re: Change of plans?

I'd say based on response, the 12" is s deffinite go, I've already started on that one, but the Lidia15 is probably down for the count. No one has shown an interest in that size. There might be an Abbey_plus, a 12" woofer and 15" waveguide. There is a little interest in that, but not enough right now for me to commit to it.

I'm very much interested in the possibility of the Abbey_plus, enough to send in a deposit to get in the queue. Would you want the same $200 per unit as a deposit/earnest money? If not what will the number be? I suspect the final cost isn't known yet but at this point it's the seed number that matters.

 

[gedlee]

Re: Re: Re: Change of plans?

I'm very much interested in the possibility of the Abbey_plus, enough to send in a deposit to get in the queue. Would you want the same $200 per unit as a deposit/earnest money? If not what will the number be? I suspect the final cost isn't known yet but at this point it's the seed number that matters.

I hate to take a deposit on this model as I'm not sure of if or when. Stay in touch though.