I want to know if it's worth it to modify my speakers.

[Seth=L]

I've been thinking about what modifications I could do to my Infinity IL10 bookshelf speakers that would fix my few qualms with them. I do apologize for a general lack of knowledge about what those problems may specifically be, but I'll try to describe them.

1. - They are a ported speaker. When the port is unplugged the bass is a bit exaggerated. One part because of the listening space and the other is no doubt due to the crossover/port tuning. I plug the ports and I lose a bit of the lower midrange that makes the speakers sound bigger (not exaggerated in this range). I hope that isn't confusing.

2. - The terminal mount sometimes buzz at certain frequencies at moderate to higher levels of playback. This is a rare occurrence, but distracting none the less with certain passages.

3.- An exaggerated hump around 150-160Hz and another up around 1000Hz I believe. That could be partly due to the room as well.

Right now in the current setup the system is setup as 2.0 in the nook of my apartment which opens into the kitchen and living room area. The ports are plugged and I get useful output down to 35Hz and audible output down to 25Hz. Overall this is very satisfactory to me, as I'm getting pretty much full range sound with substantial authority. Power is provided by a Niles SI-275 amplifier and the speakers are less than 4 ft apart and less so from the listening position, so basically near field. Sound stage is relatively wide and center stage is focused and not excruciatingly finite (meaning I can move my head around a bit and get comfortable without losing the "sweet spot").

The upper midrange and highs sound very good to me, mostly smooth until the material gets complex. This could be due to the crossover, the drivers, or possibly the source material. I'm thinking it's most likely the crossover.

Improvements that I would seek:

1. reduced middle midrange (which I define as around 1000Hz) which currently overpowers the midrange and highs a tad. It can be a bit shouty as they currently are.

3. Improving the high frequencies to not become muddled when the program gets more complex. If they could keep their composure with multiple layers of material that would help tremendously.

3. Getting rid of that buzz would certainly be nice.

I'd rather not sacrifice much if any extension if it can be helped. I know adding bracing the cabinet would likely sacrifice extension for accuracy. Perhaps I could line the cabinet walls with dynomat and that would possibly help. Currently it only has polyfill.

Advise or suggestions is what I'm looking for.


Thank you

NOTE: I may try to get a 2nd pair of the Infinity IL10 monitors from the second hand market for this "experiment" should it be worth my while. The main reason I chose this model as a candidate is that Chris (former Audioholic's resident) had talked to me long and hard about using those speakers in an upgrade was interested in doing. He seemed to believe they had a lot of potential. I'm not interested in turning them into some kind of absolutely insanely flat response speaker system, I'm interested in something simple that will make improvements on them without forfeiting their sonic character. They're easy and enjoyable to listen to.

 

[Swerd]

My short answer to your question is no. Just get some Salk or Philharmonic Audio speakers – you'll thank me later.

But your questions are worth more detailed answers.

2. - The terminal mount sometimes buzz at certain frequencies at moderate to higher levels of playback. This is a rare occurrence, but distracting none the less with certain passages.

This may be the easiest to fix. Are the binding posts mounted in a plastic cup-like insert? If so, remove the mounting screws, pull out the cup, and look if there is a gasket. Replace it with new silicone caulk or weather stripping.

3.- An exaggerated hump around 150-160Hz and another up around 1000Hz I believe. That could be partly due to the room as well.

150-160 Hz is almost certainly the room. You could try moving the speakers to various different locations to check if that changes that hump. If so, it was the room.

The other hump at ~1000 Hz is probably inherent to the woofer. Little you can do about that. Unless it's caused by not enough baffle step compensation (BFC). Your photo shows they are far enough away from the wall behind them to suggest this hump is not caused by lack of BFC. To add BFC, you would have to add a BFC circuit to the crossover. It would require better testing before you would want to do that.

2. Improving the high frequencies to not become muddled when the program gets more complex. If they could keep their composure with multiple layers of material that would help tremendously.

My guess is that more complex program material is more than the drivers can handle without sounding muddy. No crossover change would fix that.

I'd rather not sacrifice much if any extension if it can be helped. I know adding bracing the cabinet would likely sacrifice extension for accuracy. Perhaps I could line the cabinet walls with dynomat and that would possibly help. Currently it only has polyfill.

I wouldn't bother with bracing or dynomat.

Better to build your own new speakers, as here http://murphyblaster.com/content.php?f=MB27.html
http://murphyblaster.com/content.php?f=MB27.html
There is a build thread (http://forums.audioholics.com/forums/threads/building-your-first-diy-speaker-the-mb27.81354/) I posted about them using a pre-made cabinet from Parts Express, but the photo links are all dead now. If you PM me with an email address, I can send you a pdf with all the text and photos. It's worth a read as an example of what you can do with very little woodwork.

 

[Dennis Murphy]

It sounds to me like the speakers just don't have enough baffle step compensation. That would explain the apparent peak a 1 kHz, the somewhat shouty character, and the lack of clarity on demanding material. The only cure for that is a crossover redesign. Tinkering around the edges really won't help much.

 

[Seth=L]

Thank you @Swerd

The thing I worry about with most custom speakers is that the baffle is almost always flat and takes little to know accounting for early reflections one encounters in a small room, or is my assumption incorrect that the waveguide on my Infinitys helps in this regard?

I would certainly have to use a prebuilt cabinet as I have no access to work working tools or a place to do said woodwork.

Requirements are extension, high resolution yet smooth, easy to achieve sweetspot, wide and enveloping sound stage, must work well in small rooms.

I can deal with complex loads (4 ohms or so) and low sensitivity (85dB or so).

 

[Seth=L]

It sounds to me like the speakers just don't have enough baffle step compensation. That would explain the apparent peak a 1 kHz, the somewhat shouty character, and the lack of clarity on demanding material. The only cure for that is a crossover redesign. Tinkering around the edges really won't help much.

Which was what I was thinking, however I know absolutely NOTHING about speaker design and crossover implementation. What I do know is that I don't want to wreck all the things the speaker does that I like to correct a few drawbacks.

 

[Swerd]

Everything I know about BFC, especially what it sounds like when it's lacking, I learned from Dennis. So I nod my head at what he says.

The thing I worry about with most custom speakers is that the baffle is almost always flat and takes little to know accounting for early reflections one encounters in a small room, or is my assumption incorrect that the waveguide on my Infinitys helps in this regard?

If I understand it, the shallow waveguide on those Infinity tweeters serves mainly to make that dome tweeter somewhat more sensitive than it would be if mounted on a flat surface, and to allow a somewhat lower crossover frequency. I don't believe it does as much to prevent wide dispersion. That question could be answered by proper on and off-axis measurements.

Most of the off-axis sound that contributes to a good sound stage and imaging comes (in a 2-way speaker) from the woofer below the crossover point, and not from the higher frequencies of the tweeter.

I would certainly have to use a prebuilt cabinet as I have no access to work working tools or a place to do said woodwork.

Understood. That's why Parts Express and Madisound sell prebuilt cabinets. They are not cheap, but they are probably better made than what sells in the price range of those Infinity speakers. There are people who could help you with cutting the driver holes on the front baffle. Just ask.

Requirements are extension, high resolution yet smooth, easy to achieve sweetspot, wide and enveloping sound stage, must work well in small rooms.

That's why I suggested a good DIY kit. They were designed to do just what you describe. The least expensive one I have experience with is the MB27. There may be others that cost less, but I haven't heard them.

 

[Swerd]

I guess it really comes down to whether you want better sounding speakers, or you want to tinker with your Infinitys.

I read your original post as saying you want better speakers, but you may not realize it yet. I could be wrong .

 

[Swerd]

As an illustration of what Dennis said above about lack of BSC, here is a frequency response curve of an unidentified speaker.

If it had more BFC, the elevated response (blue rectangle) across the mid range would be lowered to the same level as just below 500 Hz. That's the range where the 'shouty' sound is heard. And the dip (green rectangle) in the 2.5 to 4 kHz range would be less prominent, or even eliminated. That's where complex program material can create a 'lack of clarity'.

In this 2-way speaker, the blue and green areas probably straddle the crossover frequency.

 

[KenM10759]

Interesting. Everything I know about baffle step compensation could fit on the pointy end of a pin...not the just the head of it. I have so much to learn!

if you modify those speakers it seems a poor use of time to my uneducated mind. In purely economic terms I would think they have more inherent value and a sale of them to fund an upgrade would be wiser use of resources. Fix the simple thing (rattle in the binding post) and seek an overall higher quality cabinet, crossover and driver set by following Swerd's suggestion of buying or building something fundamentally better.

 

[Jeffrey S. Albaugh]

One more thing to consider. A powered subwoofer will give you the lower octave and it will allow you to chose the Xover point between the subwoofer & your speakers. I suspect that your biggest objection might be the fact that you are in an apartment. In that case; another suggestion. A Bass tactile system, which will give you the lower octave sound, yet not disturb any neighbors around you. I have sold & installed these system mostly in condos & apartments. I have just such a Tactile system for sale here on Audioholics. Take a look at it. You don't hear the bass; you FEEL it down to your bones. You can adjust how much lower octave bass you feel (WAF). The Tactile drivers can be mounted under chairs & sofas with a wood frame. The drivers are flat & only require 3 -- 4 wood screws. Just saying.

 

[Neo_Soul]

Seth, I'm kinda late to the party but I have a similar system to yours with the ag-h550 receiver. I am running klipsch quartet speakers with mine. I bought them specifically to modify them. There is a lot of info on them about modifications and it can be done in baby steps. I suggest that if you enjoy your speakers than go ahead modify them, after all this is a hobby right?